HOLLYWOOD -- The Rock rules in The Mummy Returns. For the uninitiated, The Rock is the alter ego of third-generation pro wrestler Dwayne Johnson. In the World Wrestling Federation, The Rock is a superstar, a six-time champion excessively self-hyped in his own best-selling autobiography as "The Great One, the Chosen One, the Most Electrifying Man in Sports Entertainment -- period!"

The Rock stars as The Scorpion King in Universal's The Mummy Returns.

In Stephen Sommers' special-effects extravaganza The Mummy Returns, which opens across North America on Friday as the first of the summer's big popcorn movies, The Rock is to the movie what he is to wrestling, a charismatic villain with a bad attitude and, at 6-foot-4 and a muscular 255 pounds, a superhero's sculpted physique.

While his on-screen time is actually minimal, his impact is so huge that Universal Studios has already started shooting a spin-off movie, The Scorpion King, starring The Rock as the title character.

The action in The Scorpion King takes place a decade before the prologue sequence for The Mummy Returns, which features The Rock as a warrior leading his doomed army under the name the Scorpion King.

"I didn't know who he was," Sommers admits about The Rock. But after writing and directing the 1999 hit The Mummy, he knew he needed a boost for his sequel, The Mummy Returns. A casting agent suggested the wrestler for the role of the Scorpion King in the movie, and Sommers was pleasantly surprised.

"I found him to be really charming and fun and smart," Sommers says of The Rock. Then, within three weeks of their first meeting, The Rock showed up on the cover of Newsweek and as a host on Saturday Night Live and Sommers knew the timing was right. "I said, 'Thank God, I'm all set now!' "

The Rock is humble about making his movie acting debut, even though, in his book, The Rock Says, he is brash enough to predict his future as a movie star: "Will The Rock be the next James Dean or Cary Grant or James Stewart? I don't think so. But he could be the next Arnold Schwarzenegger -- only better looking."

Says Sommers: "He knows he can perform in front of 60,000 people, but he wanted to learn how to do it in front of a camera," says Sommers. "He was totally willing to learn and I love that in an actor, or in anybody."

As for the spin-off movie, which Sommers is writing and co-producing, it was an obvious move for The Rock. "He's so natural," says Sommers, "A natural action hero."

In person, it is Dwayne Johnson who shows up, not the swaggering The Rock, whom Johnson always refers to in the third person, as he did in his autobiography. In the book, ghost written by former Houston film critic Joe Layden, The Rock is all bombast, a fictional character pushing the outer limits of the WWF.

In the flesh, Dwayne Johnson, who turns 29 on Wednesday, is polite to extremes. At one point, he uses the word "ass" and immediately apologizes. He is articulate. He is friendly.

He is so kind and cooperative he even leads a group of reporters singing Happy Birthday into a tape recorder for Vancouver film writer Ian Caddell's eight-year-son Owen. His dad is stuck in L.A. on this interview instead of being home for the birthday celebration.

As for The Mummy Returns and The Scorpion King, scheduled for a May 2002 release, Johnson says simply: "I'm excited about it. There are all these elements that are going to make it a wonderful story.

The Rock in a scene from Universal's The Mummy Returns.

"It is about vengeance and discovery, and it's about love. It's a wonderful story about a man's rise from being an assassin with a heart of ice to a leader of thousands of men, a man with a heart of gold."

His character is strong but not invincible. Which is why he loved movies such as Rocky -- "I was a huge fan of the Rocky movies, a huge fan!" -- as well as the Indiana Jones series. "I was a huge fan of any hero who was able to show vulnerability," Johnson says.

"Of course, when I was younger, I didn't know how to describe it, but there was just something appealing to me when the guy is so big and so strong and he kicks so much butt and yet he can get his butt kicked."

As a role model for his movie career, Johnson cites Schwarzenegger. "I get the Arnold comparison, often," he says, "and that is fantastic." Schwarzenegger has passed along personal words of encouragement, as has Sylvester Stallone. "Here are two guys who have made it in this industry," Johnson says in appreciation. "They are very successful and don't have to be supportive but they have been."

Flashing his sense of humour, Johnson also does an uncanny impersonation of Schwarzenegger giving praise in his Austrian-English drawl: "De Rock, you're doing faaaaantastic, aaaabsolutely."

Johnson, who is of Samoan and African-Canadian descent, says the key to his possible success in movies is surrounding himself with "good directors, good writers, good actors." It's the same technique he used to get ahead in the scripted WWF world.

But his wrestling career is in limbo. "I'm on hold now from story lines in the WWF because it is just so difficult, as you know, filming movies." But he will return to wrestling until the physical element becomes too much. By then, he wants a real movie career.

His dream, says Johnson, is "to excel in this industry long-term, not short-term."